The number of extant stone circles (not including ring cairns , kerb cairns etc ) in Scotland and England is much less than 1,000 .
Pastcape list 337 ,of these many are ,possible , alleged , destroyed and others are actually other monument types ring cairns ,hut circles . Thom didn’t just visit , he accurately surveyed the sites . If you want to know the shape and architecture of these sites a survey is necessary , as well as Thom there are other individual surveys by others often previously recorded by Thom . This is the best we have when it comes to making a commentary on the circularity or lack of an regional variation .
Not only has Bodmin suffered from re-erections that may well be inaccurate but often it is impossible to tell the shape when many of the stones are missing or recumbent e.g. Trippet stones , 8 from the possible original 28 ,Stripple 15 from a possible 28 etc .The small circular Alturnun was re-erected leaving the small equating with circular in this area problematic . The small numbers , re-erection , possible localised features makes extrapolation problematic ,whereas the more accurate greater numbers and countrywide surveys of Thom and others , all relatively accessible provide a much better picture and this shows that circularity , even in the bigger monuments was an early feature and many of the smaller later monuments often deviated from circularity .